Fabric

A general comparison and then a more thorough examination of fabric samples using the light microscope and the SEM (Scanning Electron Microscope).

It In this exercise we will be using different pieces of fabric to to become familar with the techniques of length/area image measurement and how to interpret that data.

Density Slicing is another technique that will be covered in this exercise. It can be used with images taken from the WEB, photographed in class, laboratory or in connection with some particular project. It allows the investigator to calculate the surface area of almost anything from a landsat photograph to the fabric image on the right.

Show ImageJ application.

Go to File, Open Samples and open image FabStk. This is a view of three images of the same piece of fabric. The images are in the form of a stack. If you use the < > keys on the keyboard you can go forward and back in the stack. The first image is a photograph of the fabric, while the next two show the fabric under a light microscope and then under a scanning electron microscope

You can select the hand from the Tools Menu. Click on an image and then move it around with the .

1. Compare the LM view with the SEM view. Are the images exactly the same magnification?

Which image gives you more detail?

Any idea why?

Put your answer in the Results section.

Close FabStk

Go to File, Open Samples and open the thread images F1,and F2.

Click once on F1 which selects that image. Count the number of vertical threads across the image as accurately as possible. Record this as a whole number in Table 1 in your Results section. Now count the number of horizontal threads and record your answer. Do the same thing for the F2.

2. Which fabric weave (F1,or F2) would you want to be wearing during the Winter? Summer? Explain.

Density Slicing :

Go to Analyze, Set Measurements and the only box selected should be Area and Limit to Threshold. See image on the right> Click OK

Then go to Analyze, Set Scale. Enter the Distance in Pixels as 0, the Known Distance as 0, and the Unit of Measurement as pixels. See image on the right> Click OK

Click once on F1 which selects that image.

Go to Analyze, Measure and what you will get is the area in pixels of the entire image.

Go to Image, Adjust and Threshold. You will see two slide bars. Adjust the top slide bar all the way to the left and the bottom slide bar to 25 until you have the threads in white and all the spaces in red.(What you have done is to select everything with that pixel density out of 256.)

Now do Analyze, Measure. The area of everything that you have selected in RED has been measured in pixels.

Record the two sets of results in Table 1.

Repeat the same measurement operations for image F2 .

 

Put your answers in the Results Section.

Optional:

A. Go to File, Open Samples and open the images F1LM and Scale. The Scale image is a photograph of a millimeter ruler. The large gaps are 1 mm. or 1000 micrometers (µ). Use the Rectangle Selection tool and select a 1000 micron area. Go to Edit, Copy.(Like the example shown.)

Go to the Edit and Paste the 1000 µ portion on the F1LM image. Close image Scale. Calibrate the image in the following manner:

Use your magnifier and click on the scale. This will enlarge your view. (To go back hold down the Option key and click) Take your straight line tool and click on the left side of this scale and draw the line to the end of the scale. Go up to Analyze, and click on Measure. (You should get a reading of around 190 which is in pixels) Now go to Analyze, Set Measurements and the only box selected should be perimeter. Click OK and then go to Analyze, Set Scale. Enter the distance in pixels that you got, and then enter 1000 (1 mm. ) for the known distance. Lastly enter micrometers for Unit of Measurement Click OK

Determine the thickness of the middle strand of the second fiber from the left.

Open image SEMF1.

Calibrate this image using the scale at the bottom.

Measure the width of the middle fiber in this image and compare your result with what you obtained with the light microscope image.

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Results:

(You can also Go to File, Open Samples and Open the image Results which is a copy of this Results section. While this page cannot be printed out - at this time - it can be saved as a JPEG file to your desktop. You can then open it with any graphics program,type out the answers and then print it out from your program.

You can also enter the results on this image using the Text Tool. To do this first go to Edit, Options, Fonts and select something like Geneva - 12 pt - Bold. Then click on the Results Image in the answer space and draw out the yellow rectangle that appears and start typing. When you are finished go to Edit and Select Draw. What you have typed should now be present.)

1. Compare the LM view with the SEM view.

Are the images exactly the same magnification?

 

Which image gives you more detail?

 

Any idea why?

 

2. Which fabric weave (F1, or F2) would you want to be wearing during the Winter? Summer? Explain.

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